Assessment of ion-sensitivity of Si3N4 based feedback field effect transistor using snap-back characteristics

• Utilizes Si 3 N 4 as a novel sensing layer over SiO 2 in the ultra-steep subthreshold feedback field effect transistor (ISFBFET), introducing a robust method for enhancing ion sensitivity and device performance in ion-sensing applications. • Employs sophisticated Gouy-Chapman-Stern and site-binding models to accurately predict and analyze the ion-sensitivity of the ISFBFET, demonstrating a rigorous theoretical framework that enhances the understanding of ion interaction at the sensor interface. • Achieves unprecedented sensitivity levels at a gate work function (Φ G ) of 4.4 eV, with sensitivity values of 2.35 and 405 under constant current and voltage conditions respectively, marking a significant advancement in the field of ion-detection technology. • Offers a promising approach for the development of sensors capable of detecting biomolecules and amino acids with high specificity and sensitivity, which could have substantial impacts on biomedical research and diagnostic industries. This work discusses the sensitivity response of a feedback field effect transistor-based ion sensor (ISFBFET). To precisely predict the sensing behavior, the Gouy-Chapman-Stern and site-binding methods are used as the principle models in a detailed TCAD study. For charge binding, the deposition of Si 3 N 4 over SiO 2 is used as a sensing element. The behavior of the ISFBFET is discussed against gate work function (Φ G ) engineering and bulk pH. The performance of the sensor is analyzed using I DS -V DS , I DS -transit time, and snap-back characteristics. Sensitivity is evaluated in terms of constant current and constant voltage using snap-back characteristics and at Φ G = 4.4 eV, the highest sensitivity of 2.35 and 405 is obtained. The proposed work can help in designing FBFET based ion-sensors for sensing biomolecules or amino acids.